jdk/src/share/classes/sun/dyn/BoundMethodHandle.java
changeset 2707 5a17df307cbc
child 4537 7c3c7f8d5195
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/share/classes/sun/dyn/BoundMethodHandle.java	Tue May 05 22:40:09 2009 -0700
@@ -0,0 +1,180 @@
+/*
+ * Copyright 2008-2009 Sun Microsystems, Inc.  All Rights Reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Sun designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Sun in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+
+package sun.dyn;
+
+import sun.dyn.util.VerifyType;
+import sun.dyn.util.Wrapper;
+import java.dyn.*;
+
+/**
+ * The flavor of method handle which emulates an invoke instruction
+ * on a predetermined argument.  The JVM dispatches to the correct method
+ * when the handle is created, not when it is invoked.
+ * @author jrose
+ */
+public class BoundMethodHandle extends MethodHandle  {
+    //MethodHandle vmtarget;           // next BMH or final DMH or methodOop
+    private final Object argument;     // argument to insert
+    private final int    vmargslot;    // position at which it is inserted
+
+    // Constructors in this class *must* be package scoped or private.
+
+    /** Bind a direct MH to its receiver (or first ref. argument).
+     *  The JVM will pre-dispatch the MH if it is not already static.
+     */
+    BoundMethodHandle(DirectMethodHandle mh, Object argument) {
+        super(Access.TOKEN, mh.type().dropParameterType(0));
+        // check the type now, once for all:
+        this.argument = checkReferenceArgument(argument, mh, 0);
+        this.vmargslot = this.type().parameterSlotCount();
+        if (MethodHandleNatives.JVM_SUPPORT) {
+            this.vmtarget = null;  // maybe updated by JVM
+            MethodHandleNatives.init(this, mh, 0);
+        } else {
+            this.vmtarget = mh;
+        }
+     }
+
+    private static final int REF_ARG = 0, PRIM_ARG = 1, SELF_ARG = 2;
+
+    /** Insert an argument into an arbitrary method handle.
+     *  If argnum is zero, inserts the first argument, etc.
+     *  The argument type must be a reference.
+     */
+    BoundMethodHandle(MethodHandle mh, Object argument, int argnum) {
+        this(mh, argument, argnum, mh.type().parameterType(argnum).isPrimitive() ? PRIM_ARG : REF_ARG);
+    }
+
+    /** Insert an argument into an arbitrary method handle.
+     *  If argnum is zero, inserts the first argument, etc.
+     */
+    BoundMethodHandle(MethodHandle mh, Object argument, int argnum, int whichArg) {
+        super(Access.TOKEN, mh.type().dropParameterType(argnum));
+        if (whichArg == PRIM_ARG)
+            this.argument = bindPrimitiveArgument(argument, mh, argnum);
+        else {
+            if (whichArg == SELF_ARG)  argument = this;
+            this.argument = checkReferenceArgument(argument, mh, argnum);
+        }
+        this.vmargslot = this.type().parameterSlotDepth(argnum);
+        if (MethodHandleNatives.JVM_SUPPORT) {
+            this.vmtarget = null;  // maybe updated by JVM
+            MethodHandleNatives.init(this, mh, argnum);
+        } else {
+            this.vmtarget = mh;
+        }
+    }
+
+    /** For the AdapterMethodHandle subclass.
+     */
+    BoundMethodHandle(MethodType type, Object argument, int vmargslot) {
+        super(Access.TOKEN, type);
+        this.argument = argument;
+        this.vmargslot = vmargslot;
+        assert(this.getClass() == AdapterMethodHandle.class);
+    }
+
+    /** Initialize the current object as a method handle, binding it
+     *  as the {@code argnum}th argument of the method handle {@code entryPoint}.
+     *  The invocation type of the resulting method handle will be the
+     *  same as {@code entryPoint},  except that the {@code argnum}th argument
+     *  type will be dropped.
+     */
+    public BoundMethodHandle(MethodHandle entryPoint, int argnum) {
+        this(entryPoint, null, argnum, SELF_ARG);
+
+        // Note:  If the conversion fails, perhaps because of a bad entryPoint,
+        // the MethodHandle.type field will not be filled in, and therefore
+        // no MH.invoke call will ever succeed.  The caller may retain a pointer
+        // to the broken method handle, but no harm can be done with it.
+    }
+
+    /** Initialize the current object as a method handle, binding it
+     *  as the first argument of the method handle {@code entryPoint}.
+     *  The invocation type of the resulting method handle will be the
+     *  same as {@code entryPoint},  except that the first argument
+     *  type will be dropped.
+     */
+    public BoundMethodHandle(MethodHandle entryPoint) {
+        this(entryPoint, null, 0, SELF_ARG);
+    }
+
+    /** Make sure the given {@code argument} can be used as {@code argnum}-th
+     *  parameter of the given method handle {@code mh}, which must be a reference.
+     *  <p>
+     *  If this fails, throw a suitable {@code WrongMethodTypeException},
+     *  which will prevent the creation of an illegally typed bound
+     *  method handle.
+     */
+    final static Object checkReferenceArgument(Object argument, MethodHandle mh, int argnum) {
+        Class<?> ptype = mh.type().parameterType(argnum);
+        if (ptype.isPrimitive()) {
+            // fail
+        } else if (argument == null) {
+            return null;
+        } else if (VerifyType.isNullReferenceConversion(argument.getClass(), ptype)) {
+            return argument;
+        }
+        throw badBoundArgumentException(argument, mh, argnum);
+    }
+
+    /** Make sure the given {@code argument} can be used as {@code argnum}-th
+     *  parameter of the given method handle {@code mh}, which must be a primitive.
+     *  <p>
+     *  If this fails, throw a suitable {@code WrongMethodTypeException},
+     *  which will prevent the creation of an illegally typed bound
+     *  method handle.
+     */
+    final static Object bindPrimitiveArgument(Object argument, MethodHandle mh, int argnum) {
+        Class<?> ptype = mh.type().parameterType(argnum);
+        Wrapper  wrap = Wrapper.forPrimitiveType(ptype);
+        Object   zero  = wrap.zero();
+        if (zero == null) {
+            // fail
+        } else if (argument == null) {
+            if (ptype != int.class && wrap.isSubwordOrInt())
+                return Integer.valueOf(0);
+            else
+                return zero;
+        } else if (VerifyType.isNullReferenceConversion(argument.getClass(), zero.getClass())) {
+            if (ptype != int.class && wrap.isSubwordOrInt())
+                return Wrapper.INT.wrap(argument);
+            else
+                return argument;
+        }
+        throw badBoundArgumentException(argument, mh, argnum);
+    }
+
+    final static RuntimeException badBoundArgumentException(Object argument, MethodHandle mh, int argnum) {
+        String atype = (argument == null) ? "null" : argument.getClass().toString();
+        return new WrongMethodTypeException("cannot bind "+atype+" argument to parameter #"+argnum+" of "+mh.type());
+    }
+
+    @Override
+    public String toString() {
+        return "Bound[" + super.toString() + "]";
+    }
+}